<HTML> <HEAD> <TITLE>atan</TITLE> <STYLE TYPE="text/css" MEDIA=screen> <!-- BODY { font-family: Arial,Helvetica; } BLOCKQUOTE { margin: 10pt; } H1,A { color: #336699; } /*** Top menu style ****/ .mmenuon { font-family: Arial,Helvetica; font-weight: bold; text-decoration: none; color: #ff6600; font-size: 10pt; } .mmenuoff { font-family: Arial,Helvetica; font-weight: bold; text-decoration: none; color: #ffffff; font-size: 10pt; } .cpyright { font-family: Arial,Helvetica; font-weight: bold; text-decoration: none; color: #ffffff; font-size: xx-small; } .cpyrightText { font-family: Arial,Helvetica; font-weight: bold; text-decoration: none; color: #ffffff; font-size: xx-small; } .sections { font-family: Arial,Helvetica; font-weight: bold; text-decoration: none; color: #336699; font-size: 11pt; } .dsections { font-family: Arial,Helvetica; font-weight: bold; text-decoration: none; color: #336699; font-size: 12pt; } .slink { font-family: Arial,Helvetica; font-weight: normal; text-decoration: none; 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float1 atan(float1 a); float2 atan(float2 a); float3 atan(float3 a); float4 atan(float4 a); half atan(half a); half1 atan(half1 a); half2 atan(half2 a); half3 atan(half3 a); half4 atan(half4 a); fixed atan(fixed a); fixed1 atan(fixed1 a); fixed2 atan(fixed2 a); fixed3 atan(fixed3 a); fixed4 atan(fixed4 a); </PRE> <H1><A NAME="PARAMETERS"><A NAME="3">PARAMETERS </A></A></H1> <DL> <DT><STRONG>a </STRONG></DT> <DD> <P> Vector or scalar of which to determine the arctangent. </P> </DD></DL> <H1><A NAME="DESCRIPTION"><A NAME="4">DESCRIPTION </A></A></H1> <P> Returns the arctangent of x in the range of -pi/2 to pi/2 radians. </P> <P> For vectors, the returned vector contains the arctangent of each element of the input vector. </P> <H1><A NAME="REFERENCE_IMPLEMENTATION"><A NAME="5">REFERENCE IMPLEMENTATION </A></A></H1> <P> <B>atan</B> for a <B>float</B> scalar could be implemented like this. </P> <PRE> float atan(float x) { return atan2(x, float(1)); } </PRE><P> <A HREF="atan2.html">atan2</A> is typically implemented as an approximation. </P> <H1><A NAME="PROFILE_SUPPORT"><A NAME="6">PROFILE SUPPORT </A></A></H1> <P> <B>atan</B> is supported in all profiles but <A HREF="fp20.html">fp20</A>. </P> <H1><A NAME="SEE_ALSO"><A NAME="7">SEE ALSO </A></A></H1> <P> <A HREF="abs.html"><I>abs</I></A>, <A HREF="acos.html"><I>acos</I></A>, <A HREF="asin.html"><I>asin</I></A>, <A HREF="atan2.html"><I>atan2</I></A>. <A HREF="sqrt.html"><I>sqrt</I></A>, <A HREF="tan.html"><I>tan</I></A> </P> </BLOCKQUOTE> </BODY>